🎮 Your best scores stay on this device. No sign-up, nothing uploaded.
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Time
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Cells left
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Best time
Tap a cell and pick 1–9. On a keyboard, move with the arrows, type a digit to fill, and press 0 or backspace to clear.
Each puzzle is dug out of a finished grid one cell at a time, checking after every removal that exactly one solution remains — so every puzzle here has exactly one answer. The difficulty is set by the technique the puzzle needs, not by how many cells are blank: easy solves by following cells that have only one possible digit, medium also needs spotting a digit that fits in only one place in a row or box, and hard gets stuck on both. The same puzzle number always gives the same puzzle.
What this game does
- Easy, medium and hard, set by the technique needed
- Never a puzzle with more than one answer
- Hints that give the reason, not just the digit
- Pencil-mark notes and one-move undo
- Best time saved per difficulty
Other games
These are for fun, not diagnostic tests. Scores shift with your screen, mouse and how tired you are.